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Discussion Starter #1
at what compression would someone need a vac pump. i have a 12.38 363 and i keep pushing out intake gaskets. sometimes from back and other times from front. i am just wondering if there is too much pressure and its just pushing it out. and would a pump help with the sealing of rings i do have them lateral gas ported.
 

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Sounds like you have a crankcase venting issue. Possible PCV issue. But more than likely there is an alignment issue between the intake and cylinder heads. My engine makes over 20psi boost and has never had a intake gasket failure in 3 years, and a boosted engine would certainly make more crankcase pressure than a N/A engine. Your rings would have to be completely shot to build any real pressure. And if the rings are that bad, you should see blue smoke from burning oil in the combustion process.
 

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No never had the dipstick come out and I did forget this is a nitrous motor I'm just wondering if it's my intake I had the same problem on my old 347 with same intake this new motor only has 17 runs on dyno to tune and break in , not a street car
 

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Discussion Starter #5
I was also thinking I use 1262r intake gaskets and they are 090 think I wondering if it's not letting the intake go down far enough maybe there is a gap that I can't see between r lower intake and block
 

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Have you done a leak down test to see how well the cylinders are (or aren't) sealing? Worth doing. Never had any issue out of 1262R's even on boosted apps but have heard of others having issues. I would look at your intake bolts too. I have run into occasions where the bolts are real close to bottoming out in the blind threaded holes in the heads, and after a few times of taking them off and re-torquing them, they stretch-and bottom out, giving you a "false" torque-and it doesn't compress the gasket as much as the gasket needs. Maybe something else to look into. Just ran into this on mine; and found that Briggs and Stratton oil pan bolts fit the 29245 intake on AFR205 heads perfectly. I had a few dozen of them from doing oil pan gaskets and they work fine. They are 5/16 SEMS bolts-flat washer built in.

The vacuum pump isn't necessarily needed in any application, but it is worth some horsepower-and cleaner oil.
 

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Your engine might be a good candidate for Cometic intake gaskets. Running a vacuum pump with the horizontal gas ported rings aint a bad thing either. One of the best things I have done with my ride. Pretty good clean running engine for me with what I figure better than average power for what it is. But that is just one of the pieces of the power puzzle.
 

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I don't think the pump will help with sealing. This past weekend, ran into a fellow racer who had an intake gasket sucked in. He runs ~12 inches of vacuum on a big block chevy. So a vacuum pump isn't necessarily going to help. As mentioned, they're usually used for the cleaner oil and horsepower gain among other side benefits. But spending $800 or so on a pump kit just to fix a gasket leak isn't my idea of spending wisely. Just my opinion, FWIW. Fix the leak, find out why it's doing it and go from there. At that point, a vacuum pump kit may improve the ET and MPH.
 

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All engines have blowby. nitrous engines have more than NA engines due to bigger ring gaps and more cylinder pressure while spraying.
Installing a vacuum pump will eliminate oil leaks,help with ring seal, keep your oil cleaner, prevent oil from getting into your combustion chambers, and add some power.
The ONLY downside of a good vacuum pump system is cost, and even if you only gain 10 HP, it is a reasonable return on investment per HP.
Bill Huntington
Owner, GZ Motorsports
 

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All engines have blowby. nitrous engines have more than NA engines due to bigger ring gaps and more cylinder pressure while spraying.
Installing a vacuum pump will eliminate oil leaks,help with ring seal, keep your oil cleaner, prevent oil from getting into your combustion chambers, and add some power.
The ONLY downside of a good vacuum pump system is cost, and even if you only gain 10 HP, it is a reasonable return on investment per HP.
Bill Huntington
Owner, GZ Motorsports

Bill, thanks for your input. I will eventually be calling you guys soon; need a pump for mine.
 

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Just a few pics to get your mind going. GZ installation. With a reverse rotation water pump. OEM battery mount. Electric fan mounted in OEM shroud. My old 347 ran high 10.60's with power brakes. My 366 runs low and mid 10.50's with the same 75 MM intake.
 

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Just a few pics to get your mind going. GZ installation. With a reverse rotation water pump. OEM battery mount. Electric fan mounted in OEM shroud. My old 347 ran high 10.60's with power brakes. My 366 runs low and mid 10.50's with the same 75 MM intake.
Looks great!
 

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Here is my Aeromotive pump setup with a bracket system i made to work with the aaronp coil bracket.

 

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in the past i have run an aerospace pump and it def helped a few gaskets from seeping. however recently a lot of ppl running setups similar to mine have only been using a huge tank and lines for a breather. i really havent made up my mind if i'm gonna ditch the pump or not but if i do i'll try to post pics of new setup.
 

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B-Rad,

I wanted to ask about that alternator set-up you have. Is that a kit from somebody or did you make all of that up? I'm assembling a motor for mostly 1/4 mile enjoyment. Smog, power steering and AC are all gone. Just want to run the water pump and alternator off the crank pulley now. Looking for a painless way to assemble and have a belt line up correctly.
 

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I never had much luck keeping those cork or rubber intake gasket ends from slipping out. Remove the intake, clean the ends really well on the block and intake. Use a thick bead of gray silicon on each end. Put the intake back on before the silicon hardens. It will squeeze out and seal perfectly.
 
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